Apple’s long been rumored to be working on adding fingerprint scanning technology to its gadgets, something that appears to be confirmed in a new version of its iOS software that went out Monday.

iOS 7 beta 4, which was released to developers Monday morning, has some new code (but not a visually available feature) for biometric scanning. That technology was spotted by frequent code sniffer Hamza Sood (via 9to5Mac), who picked up on a folder inside iOS 7’s code for “BiometricKitUI.” That folder includes instructions for fingerprint recognition that can pick up on the person’s left or right thumb while holding an iPhone.

Apple spent $365 million on Authentec almost exactly a year ago. The company specialized in developing fingerprint sensors that can identify users. Authentec had Samsung, LG, and Motorola as customers before it was acquired. Regulatory filings following the sale included mention that Apple was eager to get the acquisition wrapped up to add 2D fingerprint sensors to its products.

For years it was believed that Apple would adopt near-field communications (or NFC) as both a security measure for a mobile wallet and as a communications medium between devices. The company slammed the idea of NFC last September. More recently, Apple has focused on expanding its AirDrop file-transferring technology to the iPhone and iPad inside of iOS 7 as a way for users to share things with one another.

It’s worth pointing out that details inside unreleased versions of Apple’s code do not always come to fruition immediately. Lines of code for a panorama feature were spotted as far back as 2011, but the feature didn’t make it into Apple’s iOS software until iOS 6 in late 2012. In this case, Apple’s next iPhones are expected to be a few months away, making this discovery more curious.